Method and apparatus for active control of spacing between a head and a storage medium

ABSTRACT

A slider having a slider body is provided. An electrical connection is coupled to the slider body. A first actuator is coupled to the electrical connection and adapted to displace a first portion of the slider body. Additionally, a second actuator is coupled to the electrical connection and adapted to displace a second portion of the slider body.

RELATED APPLICATIONS

This application is a divisional of and claims priority from U.S. patentapplication Ser. No. 11/201,873, filed on Aug. 11, 2005 with a title ofMETHOD AND APPARATUS FOR ACTIVE CONTROL OF SPACING BETWEEN A HEAD AND ASTORAGE MEDIUM.

FIELD OF THE INVENTION

The present invention relates generally to data storage systems. Inparticular, this invention relates to methods and structures for controlof spacing between a head and a storage medium.

BACKGROUND OF THE INVENTION

A hard disc drive system utilizes a mechanism for magnetically recordingand retrieving information that includes a head and a spinning disccoated with a thin, high-coercivity magnetic material called the media.Reliable operation of the mechanism is acutely sensitive to the spacingbetween the head and the media. Many technologies address the control ofthis spacing. In particular, various mechanisms are used to provide morereliable operations for writing data to the media and reading data fromthe media.

Information is written to the media by manipulating the magnetizationdirection of volume elements in the media surface. The magnetizationdirection in the media is changed by a switching field caused by awriter over the media surface. The electromagnet is fabricated on asubstrate. A slider can include the substrate and the writer. Magneticflux supplied by the electromagnet is sufficiently strong to change thedirection of magnetization, or write information, in the high-coercivitymedia.

It is desirable to have the flux tightly localized so that alteration ofmagnetization direction occurs only in the intended volume element, andnot in adjacent elements. The degree of localization of the flux used towrite to the media depends strongly on the separation of the writer fromthe surface of the media. Primary control of writer to media separationis done using a stiff air bearing formed by the interaction of laminarair flow caused by the spinning disc and air bearing structures on anair bearing surface of the slider.

Information is read from the media using a sensor, or reader, over themedia surface. The slider can include the reader. The reader detects thedirection of magnetization and provides a signal indicative thereof. Thestrength of the sensed direction of magnetization also largely dependson the separation between the reader and the media surface, and theability to read an isolated region of specific magnetization (i.e. a“bit” of data) also depends on the separation between the reader and themedia surface.

As product performance requirements have risen, requirements for headmedia spacing control have tightened. A secondary separation control istypically employed to meet these requirements. One control includeselectrically heating the head, which causes thermal expansion of thehead and modifies the head media spacing. The heated region protrudesfrom the air bearing surface, reducing the head media spacing. The shapeof the protrusion can be concentrated proximate the writer, with minimalprotrusion elsewhere in order to minimize adverse effects caused byother portions of the air bearing surface from getting too close to themedia. Only providing a heater proximate the writer does not allowprecise separation control between the reader and the media surface.

Additionally, only providing a heater proximate the writer can createproblems when calibrating control of the heater to provide a desiredhead media spacing. An electronic control system used to control theheater power can be calibrated on a head by head basis. The calibrationrequires heating the writer to reduce head disc separation to such anextent that the protruded region of the head contacts a lubricant layeron the media. Additional drag from the lubricant layer on the headcauses a detectable increase in an error correction signal generated bya positioning system that is used to position the head at a positionover the media. Once contact between the head and lubricant layer isdetected, the heater setting can be adjusted (for example reduced) toensure a minimal separation between the writer and the media forreliable operation that does not cause damage to the head and/or media.

However, requirements for detecting contact and writing to the media aredifferent. For detecting contact, a larger area is desirable. A largerprotrusion area can interact strongly with the lubricant layer andcreate an easily detectable error signal. On the other hand, a highlylocalized protrusion region proximate the writer will create a morereliable write operation. Furthermore, contact detection with a smallprotrusion region can create difficulty when detecting contact with themedia, which can result in damage to the head and/or the media. Becauseprotrusion of any specific area (for instance a writer pole) from an airbearing surface to near contact with the media will leave other areas(for instance a reader) further from the media, protruding a single areamay offer inadequate control over spacing between other areas. In thiscontext, head spacing or protrusion requirements for reading and writingare also different.

Electrical contacts on a slider body are limited. Contacts on the sliderhave physical size limitations due to manufacturing processes andlimited slider dimensions. Additional contacts and increased line countmay deleteriously impact suspension cost as well as decrease mechanicaland electrical performance. Use of a single contact to control multipleactuators would allow reduction of contact pads and leads connecting tothe slider.

SUMMARY OF THE INVENTION

The present invention provides a slider having a slider body. Anelectrical connection is coupled to the slider body. A first actuator iscoupled to the electrical connection and adapted to displace a firstportion of the slider body. Additionally, a second actuator is coupledto the electrical connection and adapted to displace a second portion ofthe slider body.

In another aspect of the present invention, a data storage systemincludes a media surface and a slider having a slider body supportedabove the media surface. A first actuator is adapted to actuate a firstportion of the slider body towards the media surface and a secondactuator is adapted to actuate a second portion of the slider bodytowards the media surface. An electrical connection is provided on theslider body. A power source is adapted to provide power to the firstactuator and the second actuator through the same electrical connection.

Another aspect of the invention includes a method for use in a datastorage system. The method includes providing a slider body above amedia surface in the data storage system. The slider body has a firstportion and a second portion. Contact of the second portion of theslider body with the media surface is detected. The method also includesactuating the first portion of the slider body toward the media surfacebased on contact detection of the second portion and the media surface.

Yet another aspect of the present invention relates to a device havingan electrical circuit. A first actuator and a second actuator arecoupled to the electrical circuit. A power source is electricallycoupled to the electrical circuit to provide power thereto.Additionally, the power source selectively operates the second actuatorthrough a coupling element.

These and various other features as well as advantages that characterizethe present invention will be apparent upon reading of the followingdetailed description and review of the associated drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an exemplary data storage system.

FIG. 2 is a schematic view of a slider above a storage medium accordingto an embodiment of the present invention.

FIG. 3 is a flow diagram of a method in accordance with an embodiment ofthe present invention.

FIG. 4 is a schematic view of a slider above a storage medium accordingto an embodiment of the present invention.

FIG. 5 is a flow diagram of a method in accordance with an embodiment ofthe present invention.

FIG. 6 is an exemplary circuit diagram.

FIG. 7 is a schematic diagram of electrical contacts to a slider body.

FIG. 8 is a schematic cross section of a bond pad that provides acapacitive coupling.

FIG. 9 is an exemplary circuit diagram.

FIG. 10 is a schematic diagram of electrical contacts to a slider body.

FIG. 11 illustrates graphs of power change in spacing of a first portionand a second portion with a storage medium as a function of time.

FIG. 12 is a schematic diagram of a writer having a first and a secondheater.

FIG. 13 is a schematic diagram of an alternative design for a writerhaving a first and a second heater.

FIG. 14 is a graph of power as a function of frequency of alternatingcurrent for a first heater and a second heater.

FIG. 15 is a graph of power as a function of frequency of alternatingcurrent for a first heater and a second heater.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

FIG. 1 is an isometric view of a data storage system, herein a discdrive 100 in which embodiments of the present invention are useful. Discdrive 100 includes a housing with a base 102 and a top cover (notshown). Disc drive 100 further includes a disc pack 106, which ismounted on a spindle motor (not shown) by a disc clamp 108. Disc pack106 includes a plurality of individual discs 107, which are mounted forco-rotation about central axis 109. Each disc surface has an associatedslider 110, which is mounted to disc drive 100 and carries a read/writehead for communication with the disc surface. The read/write head caninclude any type of transducing head, such as an inductive head, amagneto-resistive head, an optical head or a magneto-optical head forexample.

In the example shown in FIG. 1, sliders 110 are supported by suspensions112 which are in turn attached to track accessing arms 114 of anactuator 116. The actuator shown in FIG. 1 is of the type known as arotary moving coil actuator and includes a voice coil motor (VCM), showngenerally at 118. Voice coil motor 118 rotates actuator 116 with itsattached sliders 110 about a pivot shaft 120 to position sliders 110over a desired data track along a path 122 between a disc inner diameter124 and a disc outer diameter 126. Voice coil motor 118 is driven byservo electronics 130 based on signals generated by sliders 110 and ahost computer (not shown). Other types of actuators can also be used,such as linear actuators.

The present invention relates to controlling spacing between slider 110and its associated disc. Multiple actuators are positioned on slider 110to actuate different portions of slider 110 towards the surface of itsassociated disc. In one embodiment of the present invention, a firstactuator is adapted to a portion of slider 110 proximate a writer suchthat a localized protrusion of the writer is actuated towards thesurface of the associated disc. A second actuator actuates a largerportion of slider 110 and is used for detecting contact between slider110 and the associated surface of the disc. In another embodiment, afirst actuator is positioned proximate a reader on slider 110. A secondactuator is positioned proximate a writer of the slider 110. In yetanother embodiment, a first actuator is positioned proximate a reader onslider 110. A second actuator is positioned proximate a portion ofslider 110 and is used for detecting contact between slider 110 and theassociated surface of the disc. In these cases, a single electricalcontact positioned on slider 110, for example a bond pad, is connectedto both the first actuator and the second actuator.

FIG. 2 is an exemplary embodiment of a slider 200 above a storage medium202 according to an embodiment of the present invention. Slider 200includes a slider body 204 having a transducer layer 205. Transducerlayer 205 includes a transducer 206 having a reader and a writer foraccessing and providing data on a storage medium. Transducer layer 205also includes a first portion or region 208 and a second portion orregion 210. Storage medium 202 includes a base layer 212 and a lubricantlayer 214. As discussed below, a first actuator (herein a heater) iscoupled to slider 200 in order to actuate first portion 208.Additionally, a second actuator (herein a second heater) is coupled toslider 200 in order to actuate second portion 210. When the first heateris operated, thermal expansion of first portion 208 creates a localizedprotrusion 216 that can be used to position transducer 206 closer tostorage medium 202. When the second heater is operated, thermalexpansion of second portion 210 creates a larger protrusion 218 that canbe used for reliable contact detection between second portion 210 andstorage medium 202, in particular between second portion 210 andlubricant layer 214. Accordingly, the first heater is used during writeoperations and the second heater is used when detecting contact betweenslider 200 and storage medium 202.

FIG. 3 is a flow diagram of a method 250 in accordance with anembodiment of the present invention with reference to elementsillustrated in FIG. 2. At step 252, the second portion 210 of the sliderbody 204 is heated. Heating second portion 210 provides a largeprotrusion 218 that interacts with lubricant layer 212. At step 254,contact of storage medium 202 (herein lubricant layer 212) and thesecond portion 210 is detected. At step 256, the first portion 208 isheated to provide a desired head media spacing based on the contactdetection. As a result, slider 200 is less susceptible to damage. Thelarger second portion 210 can reliably contact lubricant layer 212without causing significant damage to slider 200 or more notablytransducer 206. Given the point at which second portion 210 contactslubricant layer 212, suitable power can be supplied to the first heatersuch that spacing between transducer 206 and medium 202 is minimized.Any form of contact detection can be utilized with the method describedabove.

FIG. 4 is a cross-sectional view of an exemplary magnetic read/writehead 260 and magnetic disc 261 taken along a plane normal to air bearingsurface 262 of read/write head 260 in accordance with an alternativeembodiment of the present invention. Air bearing surface 262 of magneticread/write head 260 faces disc surface 263 of magnetic disc 261.Magnetic disc 261 travels or rotates in a direction relative to magneticread/write head 260 as indicated by arrow A. Spacing between air bearingsurface 262 and disc surface 263 is preferably minimized.

A writer portion of magnetic read/write head 260 includes top pole 230,write pole 264, yoke 265, insulator 266, conductive coils 267 and bottompole 268. Conductive coils 267 are held in place between yoke 265 andtop pole 230 and between yoke 265 and bottom pole 268 by use ofinsulator 266. Conductive coils 267 are shown in FIG. 4 as two layers ofcoils but may also be formed of one or more layers of coils as is wellknown in the field of magnetic read/write head design. The coils 267 canbe arranged in a helical, pancake, or any other functional design. A gapcloser 231 couples top pole 230, yoke 265 and bottom pole 268. Otherconfigurations for read/write head 260 can also be used in accordancewith the present invention.

A reader portion of magnetic read/write head 260 is separated from thewriter portion by a non-magnetic spacer 232 and includes a top shield234, top gap layer 269, metal contact layer 270, bottom gap layer 271,bottom shield 272, and giant magnetoresistive (GMR) stack 273. Metalcontact layer 270 is positioned between top gap layer 269 and bottom gaplayer 271. GMR stack 273 is positioned between terminating ends of metalcontact layer 270 and bottom gap layer 271. Top gap layer 269 ispositioned between top shield 234 and metal contact layer 270. Bottomgap layer 271 is positioned between metal contact layer 270 and bottomshield 272. Other types of readers can also be used, for example thosethat utilize a CPP (current-perpendicular to the planes) geometry, suchas a tunneling magnetoresistance (TMR) reader.

In accordance with an embodiment of the present invention, a firstactuator and a second actuator are provided on read/write head 260. Thefirst actuator is positioned proximate the writer portion 260, inparticular proximate write pole 264. The first actuator is adapted toactuate write pole 264 towards disc 261. The first actuator actuates afirst portion 274 towards disc 261. As a result, write operations aremore reliable. The second actuator is positioned proximate the readerportion of read write head 260. In particular, the second actuator ispositioned proximate GMR stack 273. The second actuator is adapted toactuate second portion 275 towards disc 261. Thus, a more reliable readoperation can result.

FIG. 5 is a flow diagram of a method 276 in accordance with anembodiment of the present invention with reference to elementsillustrated in FIG. 4. At step 277, a slider is provided having a readerand a writer above a media surface. At step 278, the reader is actuatedtoward the storage medium using a first actuator. When actuating thereader towards the storage medium, a more reliable read operation can beachieved. At step 279, the writer is actuated towards the storage mediumusing a second actuator. When actuating the writer towards the storagemedium, a more reliable write operation can be achieved. It should benoted that steps 278 and 279 can be used in any order and, as discussedbelow, can be repeated successively such that reader and writeractuation is performed to achieve simultaneous actuation of both thereader and the writer.

It is worth noting that electrical contacts on a slider body arelimited. Contacts to the slider may have physical size limitations, andpreclude introduction of extra contacts. Further, electrical contactsalong the circuit connected to the slider may have limitations in countas well. Increased line count may deleteriously impact suspensionmechanical performance and cost, as well as decrease electricalproperties.

In one particular embodiment of the present invention, an electricalconnection coupled to a power source is adapted to drive differentelectrical elements on a slider body. The elements can be switches,heaters, actuators, micro-electro-mechanical systems (MEMS), and thelike. As discussed above, it is worthwhile to include two separateactuators for actuating two different portions. For example, one portioncan be adapted for reliable contact detection and the other portion canbe adapted for reliable write operations. In another embodiment, oneactuator is adapted to actuate a reader and one actuator is adapted toactuate a writer. To limit the number of electrical contacts on a sliderbody, two actuators can be driven from a single electrical contact onthe slider body. It is further envisioned that three or more electricalelements can be powered through a single electrical connection, forexample using a tiered diode set up in which different diodes arepowered using different voltage intervals. Alternatively, capacitorand/or inductors can be used with frequencies in a range of intervals.Also, it is possible to control numerous circuit elements from a singleelectrical connection and ground, such as through the use oftransistor-driven decoding of power transfer into numerous actuatorsusing a large interconnected array of conventional transistor logicintegrated onto the recording head.

FIG. 6 is an exemplary circuit diagram 280 that can be used to driveseparate actuators (in this case heaters) from a single slider bodyconnection. In this embodiment, one heater is driven by direct currentwhile the other heater is driven by alternating current. Using thecircuit illustrated in diagram 280, two separate heaters can be providedto heat different regions of a slider. Diagram 280 includes a powersupply 282, a first resistor (or heater) 284 and a second resistor (orheater) 286. The first resistor 284 heats a first portion of the sliderand the second resistor 286 heats a second portion of the slider. Bothresistors 284 and 286 are coupled to ground. Diagram 280 furtherillustrates an oscillator 288 to drive second resistor 286. Together,power supply 282 and oscillator 288 provide a power source to theelectrical circuit. A capacitive coupling 290 is further provided in thecircuit to prevent direct current from reaching resistor 286. Thoseskilled in the art will appreciate that various circuit elements canalso be used in place of capacitive coupling 290, including otherconventional circuit elements having an impedance characterized by whatis known by those practiced in the art as a large imaginary contributionto the complex impedance of the element. An example would be inductors.As a result, resistor 284 is driven by direct current from power source282 and resistor 286 is driven by alternating current created byoscillator 288. In one embodiment, resistor 284 and resistor 286 are 60ohms, although alternative resistance levels can be used. For example,resistance levels can be from 30-90 ohms. Different levels ofcapacitance can be used for capacitor 290. In one embodiment, capacitor290 has a capacitance of 70 pico farads. Other capacitance values can beused, for example from 40-100 pico farads. Different materials can beused for components of the circuit of diagram 280. In one embodiment,resistors 284 and 286 are made of chrome or a chromium alloy.

FIG. 7 is a schematic diagram of electrical contacts to slider body 204.Electrical contacts to a slider body are typically in the form of bondpads positioned at a trailing edge of the slider body. As illustrated inFIG. 7, slider body 204 includes bond pads 301, 302, 303, 304, 305, 306and 307. Bond pad 301 is used as the connection to drive both the firstresistor 284 and second resistor 286 as discussed above in relation todiagram 280. Typically, two bond pads, for example bond pads 302 and303, are used to operate a reader, while two other bond pads, forexample bond pads 305 and 306, are used to operate a writer. Bond pad304 is a grounding pad. Bond pad 307 can be used during themanufacturing of slider body 204, for example by providing an electroniclapping guide, as is known in the art.

FIG. 8 is a schematic cross section of bond pad 301 that provides acapacitive coupling. Bond pad 301 includes an electrical connection 320,which can be connected to electronics of a data storage system. A via322 directly connects electrical contact 320 and a first lead 324. Lead324 is connected to first resistor 284. Lead 326 is connected to secondresistor 286 through a capacitive coupling. A dielectric layer 328 isprovided to create the capacitive coupling 290 (FIG. 6) to electricalcontact 320. As a result, direct current provided to electrical contact320 will be supplied to resistor 284 and alternating current provided toelectrical contact 320 will be supplied to lead 326 in order to driveresistor 286.

FIG. 9 is an exemplary circuit diagram 330 that can be used to driveseparate actuators (in this case heaters) from a single slider bodyconnection in an alternative embodiment. In this embodiment, as drawn,the polarity of the power supply will deliver power preferentially toone heater because of the forward biased diode associated with thatheater. Reversal of bias polarity will drive the other heater. Using thecircuit illustrated in diagram 330, two separate heaters can be providedto heat different regions of a slider. Diagram 330 includes a powersupply 332 that provides a power source to the electrical circuit, afirst resistor (or heater) 334 and a second resistor (or heater) 336.The first resistor 334 heats a first portion of the slider and thesecond resistor 336 heats a second portion of the slider. Both resistors334 and 336 are coupled to ground. Diagram 330 further illustrates afirst diode 338 and a second diode 340, which provide coupling elementsto the electrical circuit for resistors 334 and 336, respectively. Diode338 is a forward biased diode and diode 340 is a reverse biased diode.Under forward biasing conditions, diode 338 allows power transmission toresistor 334, such that a first portion of the slider body is heated.Likewise, under reverse bias conditions, diode 340 allows power transferto second resistor 336. As a result, reversing the polarity of powerprovided by power source 332 allows resistors 334 and 336 to be poweredseparately. In one embodiment, diodes 338 and 340 can be deposited ontoa slider using amorphous or polycrystalline materials. A degree ofrectification for the diodes can be used to ensure proper operation.

FIG. 10 is a schematic diagram of electrical contacts to a slider body350 in an alternative embodiment of the present invention. Asillustrated in FIG. 10, slider body 350 includes bond pads 351, 352,353, 354, 355, 356 and 357. Bond pads 351, 352, 353, 354, 355, 356 and357 are similar to bond pads 301, 352, 353, 354, 355, 356 and 307discussed above. In this embodiment, bond pad 351 is used as theconnection to drive both first resistor 334 and second resistor 336 asdiscussed above in relation to diagram 330 of FIG. 9.

It is also worth noting that actuation of the first portion and thesecond portion described above can be realized simultaneously. Whenusing a heater to heat the first portion and the second portion, thefirst and second portions require time over which to cool and return toa state when power to the heaters is no longer supplied. Using arepeated, alternating polarity power signal in diagram 330 tosuccessively power resistors 334 and 336 allows heat capacity of thefirst and second portions to maintain an actuated state during timeperiods where power is diverted to the other heater. Since electricalresponse time of circuit 330 is faster than the rate of dissipation ofthermal energy to the first and second portions, actuation of both thefirst and second portions can be simultaneously achieved. Alternatively,alternating current and direct current can be supplied to diagram 280 inFIG. 6 to achieve simultaneous actuation of first and second actuatorsin a manner similar to that described below.

FIG. 11 illustrates three graphs including power as a function of time,spacing between a first portion and a storage medium as a function oftime, and spacing between a second portion and a storage medium as afunction of time. Graph A illustrates a power signal switching from aforward biased polarity to a reverse biased polarity as a function oftime. During time t₁, forward biased polarity provides power to a firstactuator, which causes a first portion to be actuated towards a storagemedium. Graph B, during time t₁, shows that proximity between the firstportion and the storage medium is increased. Thus, the first portion isactuated towards the storage medium. Alternatively, Graph C illustratesno actuation of the second portion towards the storage medium duringtime t₁, since no power is supplied to a second actuator. During timet₂, power is supplied to the second actuator. The proximity of the firstportion to the storage medium is reduced during time t₂. The proximityof the second portion to the storage medium is increased during time t₂.At the end of time t₂, the first portion has not returned to an initialstate. Thus, during time t₃, the first portion is closer to the storagemedium than the initial state. Eventually, continuous switching of thepower signal can allow both the first portion and the second portion toreach an asymptotic state, wherein the first portion and the secondportion are actuated close to the storage medium. In one embodiment,several cycles can be required to reach the asymptotic state.

The first and second actuators discussed above can be used withdifferent types of writers. FIGS. 12 and 13 illustrate two differentwriters, although other writers and writer configurations can be used.For example, the first heater and second heater can be on a single layeron the slider body or on different layers. FIG. 12 is a schematicdiagram of a pancake coil writer 400. A spiral pancake writer 402 can beused to provide magnetic flux to write pole 404, which includes a poletip 406 for interacting with a storage medium. A common lead 408 isconnected to a via 410. A first lead 412 is connected to a first heater414 while a second lead 416 is connected to a second heater 418. As anexample, a capacitor or diode arrangement as discussed above can bepositioned proximate via 410 to selectively utilize first heater 414 andsecond heater 418. Heater 414 is adapted to heat a localized portion oftransducer 404 such that pole tip 406 is actuated towards a storagemedium. On the other hand, heater 418 is adapted to heat a largerportion that is actuated toward the storage medium and is used forcontact detection.

FIG. 13 is a schematic diagram of an alternative design for a writer 430having first and second heaters. Writer 430 includes a helical coil 432that provides magnetic flux to a write pole 434 having a pole tip 436. Acommon lead 438 is connected to a via 440. A first lead 442 is coupledto a first heater 444, while a second lead 446 is coupled to a secondheater 448. As an example, a capacitor or diode arrangement as discussedabove can be positioned proximate via 440 to selectively utilize firstheater 444 and second heater 448. As illustrated, heater 444 is a small,localized heater designed to actuate pole tip 436 towards an adjacentstorage medium. Second heater 448 is adapted to heat a larger regionthat is used for contact detection.

The resistance of the first heater and the second heater can be adjustedto provide desired power levels to each of the first heater and thesecond heater. For example, FIG. 14 is a graph of power as a function offrequency of alternating current provided to the second heater. Thefirst heater has a resistance of 60 ohms and the second heater has aresistance of 60 ohms. In FIG. 14, the alternating current frequencyvaries from 1 MHz to 1 GHz. At approximately 300 MHz, it is illustratedthat equal power is applied to both a first heater and a second heater.In order to direct a different amount of power to either the firstheater or the second heater, a ratio of the resistance of the firstheater to the resistance of the second heater can be adjusted. Forexample, FIG. 15 illustrates a graph similar to FIG. 14 wherein theresistance of the first heater is 80 ohms and the resistance of thesecond heater is 40 ohms. The graphs illustrate that a desiredresistance of the first heater and the second heater can be selectedaccording to desired power levels. It should be noted that improvedcontrol of actuators may use simultaneous application of AC and DCpower.

It is to be understood that even though numerous characteristics andadvantages of various embodiments of the invention have been set forthin the foregoing description, together with details of the structure andfunction of various embodiments of the invention, this disclosure isillustrative only, and changes may be made in detail, especially inmatters of structure and arrangement of parts within the principles ofthe present invention to the full extent indicated by the broad generalmeaning of the terms in which the appended claims are expressed. Forexample, the particular elements may vary depending on the particularapplication for the read/write head while maintaining substantially thesame functionality without departing from the scope and spirit of thepresent invention. In addition, although the preferred embodimentdescribed herein is directed to a head for a hard disc drive system, itwill be appreciated by those skilled in the art that the teachings ofthe present invention can be applied to other data storage systems, liketape drives, or outside the area of data storage systems withoutdeparting from the scope and spirit of the present invention.

1. A method for use in a data storage system, comprising: providing aslider body above a media surface in the data storage system, the sliderbody having a first portion, which contains a writer, and a secondportion, the second portion being larger than the first portion;actuating the second portion toward the media surface with a secondactuator such that the second portion contacts the media surface;detecting contact of the second portion of the slider body with themedia surface as a result of actuation of the second portion; andactuating the first portion of the slider body toward the media surfacewith a first actuator by applying power to the first actuator that isbased on the actuation at which contact is detected between the secondportion and the media surface.
 2. The method of claim 1 whereinactuating the second portion comprises: heating the second portion ofthe slider body such that thermal expansion of the second portion of theslider body creates contact with the media surface.
 3. The method ofclaim 1 wherein actuating the first portion of the slider body includesheating the first portion of the slider body.
 4. The method of claim 1and further comprising: providing a first heater to cause thermalexpansion of the first portion of the slider body; and providing asecond heater to cause thermal expansion of the second portion of theslider body.
 5. The method of claim 4 and further comprising: utilizingthe first heater with direct current; and utilizing the second heaterwith alternating current.
 6. The method of claim 4 and furthercomprising: utilizing the first heater with a forward biased polarity;and utilizing the second heater with a reversed biased polarity.
 7. Themethod of claim 6 wherein utilizing the first heater with a forwardbiased polarity and utilizing the second heater with a reversed biasedpolarity comprises alternating between the forward biased polarity andthe reversed biased polarity fast enough that both the first portion andthe second portion of the slider body are both actuated.
 8. The methodof claim 4 wherein the second portion of the slider body is larger thanthe first portion of the slider body and the resistance of the firstheater is the same as the resistance of the second heater.
 9. The methodof claim 1 wherein providing a slider further comprises providing aslider with an external electrical connection and at least one ofcapacitive coupling or inductive coupling between the electricalconnection and the second actuator.
 10. The method of claim 9 whereinproviding a slider further comprises providing a direct coupling betweenthe electrical connection and the first actuator.
 11. The method ofclaim 10 wherein providing a slider with capacitive coupling comprisesproviding a slider with a bond pad, the bond pad comprising the externalelectrical connection, a lead, and a dielectric layer between theexternal connection and the lead.
 12. The method of claim 11 wherein thebond pad further comprises a via extending between the externalelectrical connection and a second lead that is coupled to the firstactuator.
 13. The method of claim 11 wherein the first actuator and thesecond actuator have equal electrical resistances.
 14. A slidercomprising: an electrical connection; a first actuator electricallycoupled to the electrical connection to receive direct current from theelectrical connection; and a second actuator electrically coupled to theelectrical connection through at least one of a capacitive coupling oran inductive coupling to receive alternating current from the electricalconnection and to prevent the second actuator from receiving the directcurrent from the electrical connection.
 15. The slider of claim 14wherein the slider comprises: a reader and a writer; and wherein thefirst actuator coupled to the electrical connection is adapted todisplace the reader and the second actuator coupled to the electricalconnection is adapted to displace the writer.
 16. The slider of claim 14wherein the electrical connection forms part of a bond pad, the bond padfurther comprising: a via for electrically connecting the electricalconnection to a lead that is electrically connected to the firstactuator; and a dielectric layer between the electrical connection and asecond lead that is electrically connected to the second actuator, thedielectric layer providing capacitive coupling between the electricalconnection and the second actuator.
 17. The slider of claim 16 furthercomprising a ground bond pad electrically coupled to the first actuatorand the second actuator.
 18. The slider of claim 14 wherein the firstactuator causes a first portion of the slider to extend and the secondactuator causes a second portion of the slider to extend, and whereinthe first portion of the slider is smaller than the second portion ofthe slider.
 19. The slider of claim 18 wherein the first actuator andthe second actuator are heaters, and wherein the first actuator'selectrical resistance is the same as the second actuator's electricalresistance.